My present invention concerns broadly a bearing assembly easily adjustable to provide precise alignment of the axis of a shaft to be rotatably supported by the bearing and a predetermined reference position or desired position. More particularly, the present invention relates to an adjustable bearing assembly capable of being easily adjusted to precisely compensate for the axial misalignment of a rotatable shaft when the axis of the rotatable shaft is not in true alignment with its predetermind reference position or it is out of alignment with the axis or center of its receiving bore of a machine member for supporting the shaft through a bearing means.
In virtually all modern machines, bearings are used to rotatably support shafts, and with most of the bearing structures today in use the bearing supports a rotatable shaft about the inner circumference of its inner race and is in turn supported with the outer circumference of its outer race fitted within a bore of its supporting member such as a bracket or housing. To properly support a rotatable shaft, the bearing should necessarily have the inner circumferential axis of its inner race precisely aligned with the axis of the shaft and also the outer circumferential axis of its outer race similarly accurately aligned with the axis of the receiving bore.
Today, precise manufacturing of bearings per se can be done relatively with ease. For example, it can be relatively easily carried out to make the inner circumferential axis of the inner race exactly in alignment with the axis of the shaft, and the outer circumferential axis of the outer race with both said axes of the shaft and of the inner circumference of inner race. However, it is not necessarily always easy to have bearings installed in a machine without a misalignment or an error in dimension.
For instance, in having a rotatable shaft supported through a suitable bearing means by a supporting member such as a bracket or housing, it certainly would not involve a particular difficulty to make a bearing receiving bore identically corresponding to the outer cirumference of the bearing outer race. However, if the shaft is to be supported by a pair of axially spaced bearings, it is considerably difficult to obtain true axial alignment of the two bores for receiving the bearings. Obviously more difficult is to dispose two or more shafts in a precisely parallel arrangement in a machine, and for example in order to maintain in good meshing conditions an engageable pair of gears journalled to separate shafts, it is unavoidably practised today to provide a particular mechanism for elastodynamically compensating for any error in the distance between the two shafts or for adjusting the distance between the shafts, whereby the disadvantage is encountered that the gearing has to be complex in structure and relatively large in scale.
As indicated above, even if bearings per se can be manufactured satisfactorily precisely today, it is not always feasible with ease to have the bearings installed in strict alignment with a predetermined position or positions in a machine. Further, if a precise installation of bearings can be made in a machine, when the machine is put for operation for a relatively long period of time the bearings tend to undergo misalignment due to thermal deformation, creeping and so forth. A misalignment which often occurs with the current bearing structures attributable to difficulties to obtain an accurate initial installation of bearings or due to external causes during machine operation, if occurs, would derange the function designed of a machine including bearings and give rise to undesirable phenomena such as abnormal vibration, noises, heat generation and so forth.